Hybrid networks that integrate packet networks with traditional analog and digital telephone networks are known. Hybrid networks generally include a conversion from one protocol to another protocol. For example, a hybrid network that integrates a high-speed data network, such as the Internet, with a public switched telephone network may include a conversion from an analog/time division multiplexed protocol to an Internet protocol (IP) in the path connecting the end-user to the access network. Also, an analog/TDM to IP conversion may be required at a path connecting a public switch to a transport network. Other protocol conversions may be required including conversions to and from an Asynchronous Transfer Mode (ATM) protocol.
Loop back testing in telecommunications and data networks is known. In the telecommunications art, loop back testing is used to test a customer loop to confirm that a path exists from one point to another, for example, from a central office switch to a customer premise. In data networks, a computer sends a test message to another computer that routes the message back to the originating computer for confirmation of the integrity of the path between the two computers.
Hybrid networks pose a challenge to loop back testing. In particular, since a loop back test in a hybrid network must traverse multiple protocol domains, a traditional loop back test failure is ambiguous with respect to path integrity. More specifically, a failure in a traditional loop back test in a hybrid network may indicate path integrity problems, protocol conversion problems, or even a quality of service problem. The nature of these problems varies significantly. And, solutions to the problems are dependent upon the nature of the problem.
Therefore, a need exists for an improved method of loop back testing for identifying problems in hybrid networks that include multiple protocol conversions.